Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: ordering (newest first), a result cap (up to 30), the returned fields (heart and comment counts), and a conditional visibility note about commenting after joining. It does not explain what happens past 30 comments, leaving a small gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The key facts (scope, ordering, cap, returned counts, read-only nature) are front-loaded and dense, with no filler sentences. The closing line 'Comments are other people's words' is a stylistic observation rather than operational information and slightly dilutes the otherwise tight prose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter, read-only tool with no output schema, the description covers ordering, result cap, returned counts, and the read-only boundary, which is nearly everything an agent needs. The one missing piece is whether older comments beyond the 30-item cap can be retrieved at all.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There is a single required parameter with 100% schema description coverage ('The alarm's link or code'), and the description repeats that same meaning ('from its link or code') without adding format, prefix, or resolution details. With the schema doing the documentation work, this is the baseline case.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Reads an alarm's comments') plus scope details (newest first, up to 30, includes heart/comment counts). It explicitly distinguishes itself from the write siblings: 'Only reads; posting and hearting are separate,' which separates it from post_comment and heart_alarm.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context for use (fetching an alarm's comment thread) and explicitly excludes posting and hearting by pointing out they are separate operations. It does not name the sibling tools directly, but the separation of read vs. write is unambiguous.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.